Nonradiative Energy Transfer Research Articles

Impact of Sm3+ ions on structural, thermal, optical and photoluminescence properties of ZnO–Na2O–PbO–B2O3 glasses for optoelectronics device applications

This work describes the impact of trivalent samarium (Sm3+) ions concentrations on the thermal, structural, physical, optical and photoluminescence (PL) characteristics in Zinc Sodium Lead Borate (ZnNaPbB) glasses with configuration (70-x) B2O3–10PbO–10ZnO–10Na2CO3-xSm2O3, (where x = 0.1–2.0 mol%). The glass samples were synthesized using a traditional melt-quench technique and characterized by various spectroscopic methods such as X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared (FT-IR), UV–Vis–NIR spectra, Differential scanning calorimetry (DSC) and PL emission-excitation spectra to illuminate their photonic applications. The broad band perceived in the XRD diffractogram confirmed the amorphous nature of an un-doped ZnNaPbB glass. The physical properties including thickness, density, molar volume, dielectric constant, rare earth (RE) ion concentration, field strength and molecular electronic polarizability, etc. were calculated from the standard formulae. The FT-IR spectra identify the presence of stretching vibration in BO3 and BO4 units with some additional structural and functional groups with their bond nature. The observed DSC data was used to estimate the glass transition temperature (Tg). The absorption spectra presented all the probable transitions of Sm3+ ion-doped ZnNaPbB glass and the optical band gaps were computed using Tauc's method. All the glass samples depicted band gap values over 3 eV, proving that the material is insulating. The absorption spectra were utilized to evaluate Judd-Ofelt (J-O) parameters which were further used in different radiative parameters calculations to find the luminous levels of Sm3+ ions doped ZnNaPbB glasses. The PL emission spectra of the present ZnNaPbBSm glasses parade four bands parallel to the transitions 4G5/2 to 6H5/2 (563 nm), 6H7/2 (599 nm), 6H9/2 (646 nm) and 6H11/2 (706 nm), respectively. Additionally, the evaluated values of the emission cross-section and branching ratios describe the suitability of the present ZnNaPbBSm glasses for optoelectronic applications. Further, the colorimetric parameters such as CIE coordinates (x, y) and correlated color temperature (CCT) were evaluated using PL emission data and the measured CIE coordinates are found in the reddish-orange region for the present glasses. The time decay profiles of as-prepared glasses were used to evaluate the experimental lifetime, energy transfer parameter and type of donor-acceptor interaction. The Dexter theory and Inokuti-Hirayama (I–H) fitting are used to recognize the type of interaction in non-radiative energy transfer which is responsible for the concentration quenching. The result demonstrates that the as-prepared ZnNaPbBSm glasses are applicable for optoelectronics device applications.

High-efficiency plasmonic luminescent solar concentrators based on thiol-ene polymer

Advances in solar energy harvesting technology require innovative approaches to meet the growing energy demand. In this work, we exploit the plasmonic interaction of metal nanoparticles with fluorophores to improve the optical performance of luminescent solar concentrators (LSCs). The plasmonic luminescent solar concentrators (PLSCs) with dimensions of 5 cm × 5 cm × 0.5 cm containing CsPbBr3 quantum dots (QDs) and gold nanoparticles (Au NPs) are fabricated, characterized, and evaluated systematically. As the Au NPs concentration increases, the optical performance of PLSCs exhibits, first enhancement, and then diminishment. When the Au NPs concentration is 2 × 10−4 wt%, the optimal external quantum efficiency, optical conversion efficiency, and power conversion efficiency of the PLSC reach 1.58%, 2.90%, and 0.437%, respectively. At higher concentrations of Au NPs, the non-radiative energy transfer from the CsPbBr3 QDs to the Au NPs leads to a decrease of the emission, which can be confirmed by the decreasing lifetime of the QDs. The overall optical performance of PLSCs depends on two competing effects, excitation rate and non-radiative energy transfer efficiency. Furthermore, the PLSC demonstrate the good aesthetic quality as an excellent substitute for commercial glass. We anticipate that the high optical conversion efficiency of PLSCs based on thiol-ene polymer would shed light on future application in LSCs.

Two‐Step Sequential Process for Fabricating Graphene Nanosheets Decorated with Copper Halide Nanocrystals and Their Optoelectronic Applications

AbstractNanocrystals of Cs3Cu2I5, a metal halide with promising potential as a perovskite substitute, are successfully grown on graphene nanosheets. An intermediate stage of physically exfoliated graphene nanosheets, concurrent with the formation of copper‐based seeds on graphene surface, is developed, for the first time, allowing for the subsequent growth of Cs3Cu2I5 nanocrystals (CsNCs) to obtain CsNCs‐decorated graphene nanohybrids (CsGNHs). The morphology and properties of the CsGNHs depend on the input amount of graphene nanosheets during the reaction. The photoluminescence intensity of the CsGNHs decreases with increasing graphene content, indicating that graphene facilitates nonradiative energy transfer from the CsNCs in the CsGNHs. The inherent self‐trapping exciton emission of the CsNCs is also affected by the graphene substrate. As the graphene content increases, the emission peaks of the CsGNHs broaden and diminish. The CsGNHs emit a stable solid‐state luminescence with a large Stokes shift (zero self‐absorption) under a high‐energy ultraviolet (UV) light. Consequently, the CsGNHs can act as optoelectronic transducers and selectively generate a turn‐on photocurrent response under specific‐wavelength UV light. Additionally, a new anticounterfeiting strategy is developed using the CsGNHs as a luminescent black ink to fabricate luminescent quick‐response codes with fake pixels.

FRET Based Biosensor: Principle Applications Recent Advances and Challenges.

Förster resonance energy transfer (FRET)-based biosensors are being fabricated for specific detection of biomolecules or changes in the microenvironment. FRET is a non-radiative transfer of energy from an excited donor fluorophore molecule to a nearby acceptor fluorophore molecule. In a FRET-based biosensor, the donor and acceptor molecules are typically fluorescent proteins or fluorescent nanomaterials such as quantum dots (QDs) or small molecules that are engineered to be in close proximity to each other. When the biomolecule of interest is present, it can cause a change in the distance between the donor and acceptor, leading to a change in the efficiency of FRET and a corresponding change in the fluorescence intensity of the acceptor. This change in fluorescence can be used to detect and quantify the biomolecule of interest. FRET-based biosensors have a wide range of applications, including in the fields of biochemistry, cell biology, and drug discovery. This review article provides a substantial approach on the FRET-based biosensor, principle, applications such as point-of-need diagnosis, wearable, single molecular FRET (smFRET), hard water, ions, pH, tissue-based sensors, immunosensors, and aptasensor. Recent advances such as artificial intelligence (AI) and Internet of Things (IoT) are used for this type of sensor and challenges.

A Model of the Temperature Dependence of Concentration Quenching of Luminescence in Doped Insulators

We have developed a model for the temperature dependence of the concentration quenching of luminescent materials, and have applied this model to YAG:Ce. This model of concentration quenching is based on an assumption in which, following excitation of an activator ion, there is energy migration via non-radiative energy transfer among similar ions, finally ending at a “killer” site. The temperature dependence of a single ion-ion energy transfer process is assumed to be determined solely by the overlap of the emission and absorption bands of the donor and acceptor ions. Using our previous results to calculate the temperature dependence of this overlap function, we propose a model for calculating the effect of concentration quenching on the lifetime of the luminescent ion. This model has two parameters, one of which is the average number of energy transfer jumps that occur before reaching a killer site. In the case of YAG:Ce, we show that the observed temperature dependence of the Ce lifetime at various concentrations can be explained satisfactorily using this model.

Simultaneous Dual‐Color Amplified Spontaneous Emission and Lasing from Colloidal Quantum Well Gain Media in their Own Layered Waveguide and Cavity

AbstractMicro/nanoscale semiconductor multicolor lasers offer great potential for enhanced‐performance photonic circuits. Colloidal quantum wells (CQWs) are excellent candidates as active materials for these platforms owing to their superior properties including suppressed Auger recombination and large absorption cross‐section. In this work, multicolor optical gain and lasing from the heterostructures of CQWs as the gain media in their own all‐solution processed optical cavity are proposed and demonstrated for the first time. Here, using a simple waveguide slab consisting of the thin films of green‐emitting CdSeS/Cd0.1Zn0.9S core/hot‐injection‐shell grown CQWs and red‐emitting CdSe/CdS@CdZnS core/crown@shell CQWs, a transparent low refractive index colloidal spacing layer of silica nanoparticles (NPs) is devised that critically suppresses otherwise detrimental nonradiative energy transfer between the green and red‐emitting CQWs. This multilayer configuration is key to enabling simultaneous amplified spontaneous emission behavior in two colors with low threshold levels. This layered architecture is further adapted to a whispering‐gallery‐mode cavity by fabricating a microdisk pattern directly out of these CQWs‐NPs‐CQWs colloids. The resulting device exhibits dual‐color multimode lasing both at 569 and 648 nm at the same time. This unique multicolor lasing layered architecture holds great promise for on‐chip photonic applications such as dual‐color biological imaging.

High-Performance X-Ray Imaging using Lanthanide Metal-Organic Frameworks.

Scintillating materials that convert ionizing radiation into low-energy photons hold great potential for radiation detection, nondestructive inspection, medical radiography, and space exploration. However, organic scintillators are characterized by low radioluminescence, while bulky inorganic scintillators are not suitable for the development of flexible detectors. Here, high-resolution X-ray imaging using solution-processable lanthanide-based metal-organic frameworks as microscale scintillators is demonstrated. Mechanistic studies suggest that lanthanide ions absorb X-rays to generate high-density molecular triplet excitons, and excited linkers subsequently sensitize lanthanide ions via nonradiative resonance energy transfer. Furthermore, the crystalline nature offers a delocalized electronic feature rather than isolated subunits, which enables direct trapping of charge carriers by lanthanide emitters. By controlling the concentration ratio between Tb3+ and Eu3+ ions, efficient and color-tunable radioluminescence of lanthanide ions can be achieved. When coupled with elastic, transparent polymer matrices, these metal-organic framework-based microscintillators allow the fabrication of flexible X-ray detectors. Such detectors feature a detection limit of 23 nGy s-1 , which is 240 times lower than the typical radiation dose for medical diagnosis. X-ray imaging with resolution higher than 16.6 line pairs per millimeter is further demonstrated. These findings provide insight into the future design of hybrid scintillators for optoelectronics and X-ray sensing and imaging.

Nonradiative Energy Transfer in Bi2O3/Tm2O3 Powders under IR Excitation at Liquid Nitrogen Temperature

The presented work shows the study of energy transitions in the NIR and visible regions in the system of Bi2O3 and Tm2O3 powders. Mechanisms of upconversion luminescence and NIR luminescence between two Bi3+ and Tm3+ ions at T = 80 K accompanied with nonradiative energy transfer through the vibrational levels were investigated under IR photoexcitation. The absorption bands of the samples on the reflection spectra were examined in the visible region. The values of the emission cross-section parameters were calculated for the Bi2O3/Tm2O3 complexes.

Characterization of the Interactions between Minocycline Hydrochloride and Trypsin with Spectroscopic and Molecular Docking Technology

In the current study, the interaction of minocycline hydrochloride (MC) and trypsin (TRP) was studied using fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, UV-Vis spectroscopy, and molecular docking simulation techniques. The results show that the fluorescence quenching of trypsin at different degrees can be caused by minocycline hydrochloride at different temperatures. According to the Stern-Volmer equation, the fluorescence quenching type was static quenching. By calculating critical distance, we concluded that there is a possibility of non-radiative energy transfer between minocycline hydrochloride and trypsin. The effect of minocycline hydrochloride on the secondary structure of trypsin was demonstrated using ultraviolet spectroscopy. Synchronous fluorescence spectroscopy showed that minocycline hydrochloride could bind to tryptophan residues in trypsin, resulting in corresponding changes in the secondary structure of trypsin. Three-dimensional fluorescence spectroscopy showed that minocycline hydrochloride had a particular effect on the microenvironment of trypsin that led to changes in the secondary structure of trypsin. The molecular docking technique demonstrated that the binding of minocycline hydrochloride and trypsin was stable. Circular dichroism showed that the secondary structure of trypsin could be changed by minocycline hydrochloride.

Visible luminescence and energy migration mechanism of Sm3+ in phospho-tellurite glasses by co-activating with Tb3+ ions for solid state lighting device applications

Luminescence characteristics including the energy migration mechanism of Sm3+/Tb3+ co-activated BaO–PbO–Na2O-phospho-tellurite glasses have been reported. The XRD, FTIR, UV–VIS-NIR absorption, luminescence and CIE are examined to expose their structural and optical properties. The luminescence spectra of Sm3+/Tb3+ co-doped glasses show the green emission (Tb3+ ions) and reddish-orange colour emission (Sm3+ ions) upon dual excitation at 377 nm and 484 nm. The reduction of emission intensities (Tb3+ions) and self-emission quenching effect of Sm3+ ions have been observed when concentration of Sm3+ ions increases into the glass matrix which reveals the evidence of non-radiative energy transfer from Tb3+ (sensitizer) to Sm3+ (activator) ions. The phenomenon of energy migration is also verified with the help of Forster-Dexter theory. The chromaticity coordinates of all Sm3+/Tb3+ co-activated glasses shift from greenish to yellowish region with dependence of activator's concentration. The paper highlights that the present glasses can be utilized in light emitting devices.

Plasmon-enhanced upconversion luminescence on horizontally aligned gold nanorod arrays with self-contained spacer

The growing interest in converting infrared light to visible light in many photovoltaic fields requires the development of upconversion systems with high luminescence quantum yields and stability without blinking. However, the weak and narrow absorption of rare earth ions has greatly restricted the luminescent efficiency of rare earth dopants and hampered their translation from experimental research to real world applications. In this work, horizontally aligned gold nanorod arrays with self-contained spacer and obvious polarization dependent plasmonic properties are prepared on the substrate of silicon wafers by a self-assembly method of droplet evaporation, and polarization-dependent enhancement on the upconversion luminescence of rare earth ions doped nanoparticles (NaYF4: Yb3+, Er3+) are investigated. The results show that the luminescence intensity of the nanoparticles is greatly enhanced by a factor of about 140, when the horizontally aligned gold nanorod arrays are available as a substrate. The effect of self-contained spacer of the arrays to prevent quenching of the luminescence is investigated with the introduction of an Al2O3 layer as an isolate and the adjustment of its thickness. It is found that the self-contained spacer can effectively block the non-radiative energy transfer without the need of additional spacer. In addition, the horizontally aligned gold nanorod arrays also exhibit excellent optical polarization anisotropy. As the polarization angle of the incident light gradually increases, the intensity of the fluorescent radiation decreases, which is interpreted and analyzed by simulating the near field distribution. This strategy not only provides a powerful solution to build high-efficiency surface enhanced fluorescence systems, but also suggests a new pathway to realize the polarization-selective excitation of upconversion luminescence.

Probing the binding interactions between perfluoroalkyl carboxylic acids and adenosine A2A receptors by spectroscopic techniques, molecular simulations and quantum chemistry

The binding interactions of perfluorobutyric acid (PFBA), heptafluorobutyric anhydride (HFBA), and ethyl heptafluorobutyrate (NSC3936) with the adenosine A2A receptor (A2AR) were investigated using multiple-spectral (fluorescence, ultraviolet–visible (UV–Vis) absorption, three-dimensional (3D) fluorescence, and Fourier Transform infrared (FT-IR) spectroscopy) and computational simulation methods. Steady-state fluorescence and UV–visible spectroscopy indicated that PFBA, HFBA, and NSC3936 caused an intrinsic fluorescence quenching of A2AR by static quenching and non-radiative energy transfer. The results of 3D fluorescence and FT-IR spectroscopy showed that the presence of PFBA, HFBA, and NSC3936 induced changes in the secondary structure of A2AR. Combined with thermodynamic analysis, molecular docking and quantum chemistry investigations, our results suggest that the association of PFBA, HFBA, and NSC3936 with A2AR was driven by hydrophobic forces and the formation of hydrogen bonds (H-bonds). The binding constants for the three PFCAs studied range from 8.27 × 106 L·mol−1 to 1.80 × 107 L·mol−1 at 298 K. Molecular dynamics (MD) simulations indicated that A2AR formed stable complexes with PFBA, HFBA, and NSC3936, and validated the existence of electrostatic interactions in the HFBA-A2AR complex. Furthermore, the results from the MD simulations were consistent with the thermodynamic analysis results.

Effect of radiative and nonradiative energy transfer processes of light-emitting diodes combined with quantum dots for visible light communication

Though light-emitting diodes (LEDs) combined with various color conversion techniques have been widely explored for VLC (visible light communication), E-O (electro-optical) frequency responses of devices with quantum dots (QDs) embedded within the nanoholes have rarely been addressed. Here we propose LEDs with embedded photonic crystal (PhC) nanohole patterns and green light QDs for studying small-signal E-O frequency bandwidths and large signal on–off keying E-O responses. We observe that the E-O modulation quality of PhC LEDs with QDs is better than a conventional LED with QDs when the overall blue mixed with green light output signal is considered. However, the optical response of only QD converted green light shows a contradictory result. The slower E-O conversion response is attributed to multi-path green light generation from both radiative and nonradiative energy transfer processes for QDs coated on the PhC LEDs.

Ultrahigh Color Conversion Efficiency Nano-Light-Emitting Diode With Single Electrical Contact

Realizing full color GaN-based micro- and nano-light-emitting diode (nLED) displays with quantum dots (QDs) being the color conversion media remains challenging because of the limited QD color conversion efficiency (CCE). In this article, by using GaN-based nanorod LED as the light source and exciting the QDs by nonradiative energy transfer (NRET) method, a nanorod LED with ultrahigh CCE has been realized. At the same time, a single electrical contact alternating current (ac)-driven electroluminescence (EL) method is adopted to investigate the relationship between frequency and nLED performance. Different from the double terminal injection mode, on the premise of lighting up the nanorod LED, the ac-driven can also avoid the necessity of external p-type and n-type electrodes, thus simplified the manufacturing process of LED. The final optical measurement shows that the CCE of this hybrid color conversion nLED driven by single contact electrode can reach up to 86.67% under the ac voltage of 60 V and an ac frequency of 14.2 MHz, which shows that the energy utilization efficiency can be effectively improved by NRET.

Steady-state and fluorescence lifetime quenching of self-assembled diphenylalanine/coumarin nanostructures as a method to determine dissolved O2 in water

A fluorescent system formed by the combination of coumarin derivative and self-assembled peptide nanostructures was used as sensing system to determine dissolved oxygen (O2) in water samples. Detection was based on the sensing system fluorescence quenching by O2, measured by steady-state and time-resolved fluorescence spectroscopy and Stern-Volmer plot to correlate fluorescence intensity to O2 concentration in the samples. Also, fluorescence lifetime decays informed about the mechanisms in which the quenching is occurring, indicating that the sensing system is highly sensitive and selective to O2, since quenching occurs by a non-radiative energy transfer from electronic excited singlet states of the system to the O2 molecule. This process was evidenced by the system fluorescence lifetime decrease, yielding Singlet O2 as indicative that this system can also find other technological applications.

Interparticle energy transfer between NaNdF4 and NaYbF4 in self-assembled nanostructures

Förster resonance energy transfer (FRET) is a widely used spectroscopic technique. The development of donor–acceptor combinations is essential to advance this technique. To make the energy transfer efficiency independent of the external environment, we explored the potential of constructing donor–acceptor combinations with lanthanide ion-doped nanoparticles (LNPs), in which the 4f electrons of the lanthanide ions are shielded by the 5s and 6p electrons. Non-radiative energy transfer between LNPs was demonstrated in self-assembled nanostructures and core–shell structure of LNPs was used to control the distance between donor and acceptor in self-assembled nanostructures. The emission intensity ratio of donor and acceptor illustrates that the energy transfer efficiency decreases significantly with increasing distance and the effective energy transfer distance is 8.5 nm, showing the potential of using LNPs as donor–acceptor pairs in the construction of distance-dependent energy transfer system.

Exploring the binding characteristics of bovine serum albumin with tyrosine kinase inhibitor entrectinib: Multi-spectral analysis and theoretical calculation

Entrectinib (ENB) is one of multi-target tyrosine kinase inhibitors, which is mainly used for treating neurotrophic tyrosine receptor kinase gene fusion positive solid tumors. The binding characteristics of ENB and bovine serum albumin (BSA) were studied by experiments and theoretical calculations. The steady-state fluorescence showed that ENB quenched the fluorescence of BSA through mixed quenching, and ENB was dominated by static quenching at low concentration. ENB and BSA had a moderate affinity, formed a complex with a stoichiometric ratio of 1:1 and the binding constant of about 105 M−1 at 298 K, and Förster non-radiative energy transfer occurs. According to the driving force competition experiment, thermodynamic parameter analysis and theoretical calculation, hydrogen bond, van der Waals force and hydrophobic force were the main factors affecting the stability of the ENB-BSA complex. Molecular docking and site markers competition showed that ENB spontaneously bound to the Site III of BSA so that ENB could make the skeleton of BSA loose, the spatial structure of BSA changed (α-helix decreased by 3.1%, random coil increased by 1.7%), and the microenvironment of Tyr and Trp residues changed. The existence of Co2+ metal ions can enhance the binding effect, thus prolonging the half-life of ENB in vivo, which may improve the efficacy of ENB, while Ca2+, Cu2+ and Mg2+ metal ions will reduce the efficacy of ENB.

Enhancement of Light Extraction Efficiency and Suppression of Roll‐Off Characteristics of Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes by Inserting Nanoscale Pixel‐Defining Layer

AbstractThermally activated delayed fluorescence (TADF) organic molecules are considered the most suitable for blue organic light‐emitting diodes (OLEDs) after extensive research; however, they are plagued by issues of internally guided light and the roll‐off characteristics contributed by triplet exciton‐utilized emission. Thus, this study leverages exciton diffusion guidance and energy extraction to simultaneously achieve optical efficiency enhancement and roll‐off characteristic suppression of mixed‐host blue TADF OLEDs. The array of nanopixels, defined by the inserted nanoscale pixel‐defining layer (nPDL), spatially separates the excitons and polarons, resulting in the exacerbation of triplet quenching by securing exciton diffusion. Furthermore, through the formation of a metal cathode with a corrugated profile, nonradiative energy transfer to the surface plasmon polaritons is capitalized via Bragg diffraction, thereby boosting the emission efficiency. The structure of the nPDL is judiciously determined by finite‐difference time‐domain computational analysis. Consequently, the device with the optimized nPDL demonstrates 88.4%, 118.8%, and 108.8% improvements in external quantum, current, and power efficiencies, respectively, compared to the reference. Moreover, the critical luminance, which quantifies the degree of roll‐off, is improved by 83.7%. This pioneering demonstration of hybridizing the material combination and nanopatterning techniques is expected to provide new insights for designing high‐performance OLEDs.

Energy transfer and color-tunable emission in trivalent terbium/europium doped multi-component borosilicate glasses for white light-emitting diodes under ultraviolet excitation

Multi-component sodium borosilicate glasses incorporated with trivalent terbium and europium ions in single and dual combinations via melt-quench technique were synthesized. Glasses doped with terbium and europium displayed intense green and red colors, respectively. The addition of various contents of europium ions to a pre-optimized content of 1.0 mol% terbium resulted in efficient energy transfer. The process of energy transfer was analyzed by studying the overlap of emission and absorption spectra, luminescence properties, the decay of donor (terbium) emissions, the energy level scheme and energy transfer parameters (η and P) in the terbium/europium codoped glasses. Emission spectra and lifetimes of terbium (sensitizer) are decreased with the rise of europium content at 351 nm excitation due to sensitization of europium by terbium. The energy transfer between these ions is analyzed through Dexter's theoretical model, Reisfeld's approximation, and Inokuti-Hirayama models, which confirm that the non-radiative energy transfer from terbium to europium is predominantly governed by dipole-dipole interaction. The chromaticity coordinates are presented to comprehend the color tenability from green to red via yellow due to the co-doping of terbium to europium, to confer the suitability of this combination for achieving solid-state/ indoor lighting applications.

Interactions between polycyclic musks and human lactoferrin: Multi-spectroscopic methods and docking simulation.

Galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8-hexamethylcyclopenta-γ-2-benzopyrane; HHCB) and Tonalide (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene; AHTN) are "pseudo-persistent" pollutants that can cause DNA damage, endocrine disruption, organ toxicity, and reproductive toxicity in humans. HHCB and AHTN are readily enriched in breast milk, so exposure of infants to HHCB and AHTN is of concern. Here, the molecular mechanisms through which HHCB and AHTN interact with human lactoferrin (HLF) are investigated using computational simulations and spectroscopic methods to identify indirectly how HHCB and AHTN may harm infants. Molecular docking and kinetic simulation studies indicated that HHCB and AHTN can interact with and alter the secondary HLF structure. The fluorescence quenching of HLF by HHCB, AHTN was static with the forming of HLF-HHCB, HLF-AHTN complex, and accompanied by non-radiative energy transfer and that 1:1 complexes form through interaction forces. Time-resolved fluorescence spectroscopy indicated that binding to small molecules does not markedly change the HLF fluorescence lifetime. Three-dimensional fluorescence spectroscopy indicated that HHCB and AHTN alter the peptide chain backbone structure of HLF. Ultraviolet-visible absorption spectroscopy, simultaneous fluorescence spectroscopy, Fourier-transform infrared spectroscopy, and circular dichroism spectroscopy indicated that HHCB and AHTN change the secondary HLF conformation. Antimicrobial activity experiments indicated that polycyclic musks decrease lactoferrin activity and interact with HLF. These results improve our understanding of the mechanisms involved in the toxicities of polycyclic musks bound to HLF at the molecular level and provide theoretical support for mother-and-child health risk assessments.